Carburetor for high-pressure fuels



Nov. 2, 1943. I o. L. G'ARRETSON I 2,333,167

' CARBURE'TOR FOR HIGH PRESSURE FUELS Filed NOV. 15, 1941 PRiMARY REGULATOR ZERO REGULATOR INVENTQR OWEN 1.. GARRETSON mum Patented Nov. 2, 1943 CARBURETOR FOR HIGH-PRESSURE FUELS Owen L. Garretson, Detroit, Mich., assignor 'to Phillips Petroleum Company, a corporation of Delaware Application November lfi, 1941, Serial No. 419,346

7 Claims.

This invention relates to carburetors and more particularly it relates to a type of carburetor especially adapted for use of gasoline having vapor pressure higher than normal, in which the normally gaseous hydrocarbons are separated from the normally liquid hydrocarbons, and the two phases carbureted separately but in the same overall ratio as the ratio in which they separate from the high vapor pressure fuel, and the regulation of the relative liquid and gaseous phase flow to the engine being electricall controlled and operated.

For automotive uses, the conventional carburetor is one in which liquid gasoline of from approximately 9 to 12 pounds Reid vapor pressure is used as fuel. Some stationary internal combustion engines operate on natural or artificial gases, and in some regions trucks, busses and even motor-cars are propelled by internal combustion engines which are fueled by compressed gases. The latter engines are equipped. with special type carburetors for mixing the gas with air to form the combustible fuel mixture.

For each of these above-mentioned types of fuel, carburetors needoperate only on one phys ical phase, that is all liquid or all gas.

I have devised a carbureting system which is designed to carburet a two phase fuel, that is, a fuel which is composed of liquid and normally gaseous hydrocarbons under pressure. Fuels of this class may be such as high vapor pressure natural gasoline or even liquefied petroleum gases or mixtures thereof. In my system the hydrocarbon fuel is separated into liquid fuel and gaseous fuel, and each is carbureted separately or together in various ratios, the overall carburetion of the gas and liquid however being in the same ratio. These fuel components, which separate at a given temperature and pressure, exist in the original fuel. The changes in carhuretion from all gas to all liquid, or vice versa, or largely gas to largely liquid, say 75% gas-25% liquid to 75% liquid to 25% gas, or the reverse, are electrically controlled and operated.

An object of my invention is to devise a carburetion system and carbureting device for use with high vapor pressure hydrocarbon fuels.

A further object of my invention is tofurnish a carburetion system in which the high vapor pressure fuel is separated into liquid fuel and gaseous fuel and each carbureted separately or s multaneously.

A still further object of my invention is to furnish a carburetion system for use with fuel containing liquid hydrocarbons and gaseous hydrocarbons, the change in carburetion from liquid fuel to gaseous fuel, or from gaseous fuel to liquid fuel, or from predominantly liquid fuel to predominantly gaseous fuel, or the reverse, being controlled according to liquid levels in' a phase separating chamber and electrically operated.

Still other objects and advantages will be realized by those skilled in the art by a careful study of the following disclosure.

Figure 1 illustrates diagrammatically one embodiment of my invention showing the electrically controlled and operated carburetion system.

Figure 2 is a fragmentary section of the liquid carburetor ll of Figure 1.

Referring to the figure, numeral I represents a vaporizing chamber in .which the normally and thermoregulator 6. Heating fluid from the cooling system of an internal combustion engine enters jacket 5 through line 1 and exits through line B, the flow being controlled byithecontrol valve 9. The thermostatic valve 9 and regulator 6 are of a conventional type and control the temperature of the vaporization chamber. Float I0 is of a double kidney type and is guided during vertical movement by an oval guide bar IDA which passes through an oval slot in the connection between the two float sections. The float is provided with upper and lower contact members 'II and 29, respectively. The fuel vapor from the vaporizing chamber passes through a zero regulator 12, gas line I3, control valve 14 and into the gas carburetor l5. The zero pres- A solid connection 18 is formed between the gaseous and liquid intake tubes to provide a support for the throttle linkage to be hereinafter described. Rod I9 from foot throttle, not shown, is attached by means of arm 20 to disc 2| which is pivoted at MA to the side of connection l8. Control link 22, bevelled longitudinally, is adapted to slide in a correspondingly shaped channel in the disk 2|. To either end of slide link 22 is attached throttle valve rods 25 and 26, the valve rod 25 operating butterfly throttle valve 21 and valve rod 26 operating the butterfly throttle valve 28.

Electrical switch 30, positioned in the vapor or gas accumulation portion of vaporizing chamber i in any suitable manner operates through relay 32 to cause the armature of the reversible electric motor 33 to rotate. To this armature is attached a worm gear 34 which in turn meshes with gear wheel 35 which upon rotation turns clutch arrangement 36. wheel 35, clutch assembly 36 and turn screw 31 are obviously necessary mechanical parts but sincethey form no part of myinvention, are omitted in the interest of clarity. Member 38; is provided with a threaded longitudinal passage which loosely receives the turn screw 31. The lower portion of member 38 is hollow and of sufficient cross section and length to permit some longitudinal travel of the head on the bottom of the turn screw 21. To the bottom of said member 38 is attached control wire 23. The

other end of control wire 23 is attached to an arm 22A on slide link 22. The control wire slides through a Bowden sheath 24, held stationary relative to the disc 2|. It is obvious that vertical movement of member 38 is communicated to control link 22, moving the same longitudinally in the aforementioned channel in disc 2!. Thus the upper ends of rods 25, 2B are moved nearer to or farther from pivot point 20A, as the case may be, and the relative degree of opening of throttles 21, 28 for a given amount of rotation of disc 2| is varied in accordance with the displacement of member 22 from a central or symmetrical disposition relative to center MA. When this'displacement is to the left, for example, the movement of butterfly 2? for a given amount of disc rotation will be increased and that of butterfly 28 will be decreased proportionally.

A rod 41 is attached at one end to member 33 by pivot 4Z3, supported by fulcrum it, and the other end attached by a pivot to diaphragm pin Supports for said gear 42 of a volume displacer 48. Volume displacer Y 48 is composed essentially of open air chamber causes the switch 3! to close and by means of relay switch 49 the armature of motor 33 rotates in the reverse direction from that when switch 30 is closed. Storage battery 50 furnishes electricity for the operation of the relays 32 and M; aswell as for the operation of the motor 33. The electrical circuit shown in the drawing is purely diagrammatical, of course, and any suitable arrangement may be employed.

In the operation of my carburetion system, hydrocarbon fuel comprising natural gasoline, high vapor pressure natural gasoline containing substantial quantities of normally gaseous hydrocarbons dissolved therein, for example, 20 or 40 lb. Reid vapor pressure natural gasoline, flows from the fuel storage tank, not shown, under storage pressure through line 2, pressure reducer 3 and line 4 into the vaporizing chamber I. The fuel at reduced pressure in vaporizer l, e. g. 0.5 to 2 lbs. per sq. in., evolves as vapor some of the normally gaseous hydrocarbons, and the amount of vapor formed is dependent upon the specific hydrocarbons present in the fuel and upon the pressure and temperature maintained within said chamber. I have found that by maintaining a temperature of from to F. at essentially atmospheric pressure or slightly above, excellent gas-liquid separation is obtained when using natural gasoline of from 20 to 40 pounds Reid vapor pressure. The pressure in the vaporization chamber remains substantially constant under normal conditions. Provision for warming of the liquid fuel in the vaporizing chamber to accelerate the gas evolution is made in the form of the water jacket 5. Hot water from the engine cooling system, not shown, enters the jacket through tube 1 and leaves through tube 8, the flow being controlled by the temperature bulb or thermoregulator 8 and control valve 9 in said incoming hot wa-- ter line I.

The separated vapor accumulates in the upper portion of the vaporizing chamber l and said vapor or gas passes therefrom by way of tube l3 to the vapor or gas section l5 of the dual carburetor. The zero regulator l2 controls or maintains the desired pressure ,in the vaporizing chamber while at all times permitting gas to flow from said chamber to the vapor carburetor l5. Control valve I4 is inserted in the gas line l3 at a point near said vapor carburetor to prevent vacuum or suction from the carburetor jet. not shown, from backing up said vapor line, and to adjust the flow of vapor to correspond to the air flow that will pass through the vapor carburetor venturi.

The liquid hydrocarbon fuel from the bottom of vaporizing chamber, l passes through tube or pipe l6 into the float chamber HA carburetor I'I.

When liquid fuel from the pressure storage tank, not'shown, passes by way of pressure reducer 3 and line 4 into the vaporizing chamber I, the liquid level in said vaporizing chamber rises in case the separated vapor is being withdrawn and carbureted more rapidly than the residual gas-free liquid. Upon the continued rise in liquid level, the float l0 rises to such a point that the upper contactor H closes the upper switch 30 completingan electrical circuit to the relay 32. This said relay operates to cause the armature oi the electric motor to rotate in a clockwise direction causing internally threaded member 38 of the cable assembly to rise communicating movement to cable 23 and moving slide link 22 from right to left, i. e., from the gas carburetor it toward the liquid carburetor l1. Assuming that previous to this slide link movement, said slide link was in an intermediate position, the above mentioned movement then causes the slide link to move toward liquid of the liquid carburetor side, then upon operation of the manual foot throttle, not shown, through the throttle rod l3 and associated parts, the buttercenter position toward the liquid carburetor side, thereby causing butterfly valve 21 to open wider for a definite position of the foot throttle (not shown)--throttle rod l9, arm 20, and disc 2| assembly. At idling speed the link may travel to its extreme position until the pivot point for arm 26 coincides with the disc pivot 2IA. When this occurs the gas throttle remains fully closed. To prevent prolonged operatlonpf the motor 33 in either direction, with the resultant full use of liquid fuel to the exclusion of all gaseous fuel and vise 'versa, the volume displacer apparatus 48 is attached to the liquid fuel line l5 s0mewhere along its length or connected directly .to the vaporizer. This volume displacer is composed of-.a diaphragm 43, atmospheric air space 46 and liquid fuel space 44. To the diaphragm 43 is attached diaphragm pin 42, as shown, and this pin is pivoted to one end of rod 41, the other end of said rod being pivoted to the internally threaded member 33, at pivot 40. 'Said rod is pivoted to fulcrum 4| to permit unobstructed movement.

During periods of idling or low speed when fuel is not being consumed at a rapid rate, the liquid level in the vaporizing chamber will very slowly fall or very slowly rise, dependent upon the given position of the slide link 22. Assuming that the said slide link is on the gascarburetor side and the liquid level slowly rises until the float connector I I closes switch 30 to start the motor 33. The closing of this upper switch 30 starts the said motor in a clockwise direction rotating the clutch 36 and turn screw 31,

the internally threaded member 38 rises thereby pulling cable 23, causing the slide link to move from the gas carburetor side toward the liquid carburetor side. This movement tends to diminish the rate of carburetion of gas and to increase the rate of carburetion of liquid fuel, thereby decreasing the rate of liquid fuel rise in the vaporizing chamber. But during periods of slow speed or idling, the liquid level change is 7 very slow resulting in relatively long periods of electric motor 33 operation. A long period of electric motor operation in the above'direction will cause the slide link to travel its limit toward the liquid carbureting side with the result that gas or vapor carburetion will cease in favor of all liquid carburetion. When this change becomes effective, then the liquid level in the vaporizing chamber begins to drop and the drop continues until the lower float connector 29 causes switch 3| to complete the electrical circuit through relay 49 resulting in the operation of the electric motor 33 in the reverse direction from that caused by throwing off the upper switch 30'and relay 32. The electric motor then causes the slide link to move from left to right or from the liquid side to the vapor side of the dual carburetor, resulting then in the carburetion of proportionally more gas than liquid. In case the liquid level remains at a sufficiently low mark in said vaporizer for an extended period 22 further toward the liquid side.

of time, the electric motor 33 continues to op-- erate resulting in the movement of the slide link 22 all the way over to the right on the gas side so that only vapor or gas is carbureted. This condition then removes vapor alone from thevaporizing chamber l allowing the liquid to remain therein, causing therfore the liquid level to rise until the upper contactor closes switch 30 causing slide link 22 to move to the liquid side, as above described.

Summing these above described steps, one may conclude that if switch 30 and switch 3| remain closed for relatively long periods of time the slide link 22 will alwaystfavel its limit and either all gas or all liquid will be carbureted. The liquid level will alternately rise and fall. While this condition permits satisfactory operation it is not especially desirable because of the different octane characteristics of the liquid and gaseous phases which result in inconsistent operation. The ideal condition, therefore, is where the fractions of the fuel are carbureted simulta-- neously and. in the ratio of their separation. This latter condition is realized by use of the volume displacer assembly 48, as follows:

During light load on idling operation, as above described, when the upper float contactor Ii closes and holds closed switch 30 for an extended period of time causing the slide link to change over to all liquid carburetion the electric motor 33 in addition to operating said slide link 22, also moves rod 41. When slide link 22 is moving toward the liquid side the rod 41 moves in such a manner as to pull diaphragm 43 downward thereby causing liquid fuel from line it to accumulate in volume space 44. fuel flows into this space or chamber 44, the liquid level in the vaporizing chamber is caused to drop more rapidly than if the volume displacer assembly were not functioning. As soon as space 44 contains sufflcient volume of liquid in relation to the liquid level in vaporizer l, the level in said vaporizer drops sufliciently to open switch 30 thereby stopping the electric motor 33 before the slide link 22 has travelled itslimit toward 100% liquid carburetion. This step may take place rather rapidly, in fact so rapidly that the slide link 22 may not have moved a suflicient distance togive simultaneous and stable liquid and gas carburetion, in which case as soon as the diaphragm 43 stops its downward movement, the liquid level in vaporizer I begins to rise again until switch 30 closes to operate motor 33 in the same direction as before and to move slide link When this movement begins, the diaphragm 43 also moves further downward taking in liquid fuel and causing the liquid level in vaporizer l to drop again to open the switch so. This intermittent automatic operation continues until a balance is obtained and the liquid and gas fractions are carbureted at approximately equivalent rates and the liquid level in vaporizer I then remains essentially fixed.

In case fuel consumption is more rapid than in the above example, the periods of operation of When liquid are such that the electric motor will be energized only a few seconds at a time.

When the liquid level in the vaporizing chamher! is low and the lower float contactor closes switch 3|, steps the reverse to those above described, take place. The electric motor turns in the opposite or counterclockwise direction causing slide link 22 to move from the liquid side to the gas side. At the same time diaphragm 43 .moves upward to displace liquid fuel from the space 44 into the liquid fuel line I6. This displaced liquid causes a rise in liquid level in the vaporizing chamber which rise is sufficient to cause float ID to rise and permit opening of the electric switch 3|, In case the liquid level still is being lowered, switch 3i again closes causing slide link 22 to move farther toward the gas side of the dual carburetor, and this operation so continues until the control link 22 has reached an intermediate position permitting liquid and gas to be carbureted in'the ratio in which they separate. Then following this adjustment the liquid level in the separating or vaporizing chamber remains essentially constant until operating conditions change in such a manner as to necessitate a recharge to establish new equilibrium conditions.

When the liquid level is low in chamber l and the engine is operating under full load with a high rate of fuel consumption, the periods of operation of the electric motor for changing from mostly liquid to mostly gas carburetion are very short and ordinarily fewer in number than during periods of idling to reach an equilibrium condition in which liquid and gas fractions are carbureted in approximately the same ratio in which they separate.

There are then two conditions of equilibrium within the vaporizing chamber I, that is two conditions in which vapor and liquid fractions are carbureted in the same ratio in which they are separated from the original fuel. The first condition results when the vaporizing chamber I is essentially full of liquid and the float Hl'operating through the upper contactor ll, switch 30 and motor 33 positions the control link that the separated gas and residual liquid hydrocarbons are carbureted in such relative amounts that'the liquid level in the chamber remains essentially constant. The second equilibrium condition results when the liquid level is low in the chamber i and the float it operates in conjunction with lower contactor 29, switch 3|, motor 33, slide link ZZ'and connecting parts to cause the separated gas and residual liquid hydrocarbons to be carbureted in the ratio of their separation. Thus essentially these two conditions are similar, the only practical difference being that in one case the liquid level in the vaporizing chamber l is high and in the other case the liquid level is low. Which of these two conditions is present'and in operation is dependent upon previous conditions, that is, when the slide link 22 permits mostly gas to be carbureted, the liquid level in vaporizing chamber will be rising and the resultantcondition of equilibrium will occur at the high level. Whereas if the slide link 22 has been permitting mostly liquid hydrocarbons to be carbureted, then the equilibrium following will occur at a low liquid level in the said vaporizing chamber.

In mycarburetion system, as above fully described, one may use as fuel natural gasoline, high vapor pressure natural gasoline, high vapor pressure refinery gasoline, liquefied petroleum gases, mixtures of natural gasoline and/or refinery gasoline with normally gaseous hydrocarbons under pressure.

The electric switches 36 and 3| may be of conventional design, the essential prerequisite being that they operate easily and in a hydrocarbon gas or liquid atmosphere. However, these switching arrangements, may be such that mechanical devices within the vaporizing chamber l actuated 'by float I0 and the corresponding connectors H and 29, extend through the chamber walls and actuate switches mounted on the exterior of said vaporizing chamber. The switches, too, must be explosion proof.

The rod member 41 connecting threaded member 38 and diaphragm pin 42 is shown in its simplest form, and may be used as shown or may bemodified or replaced by another appadesign and selection of materials of, construction ratus as long as the vertical movements of member 38 are transmitted to the diaphragm pin 42, so that both members may move freely and unobstructed. One simple method of accomplishing this result is that the pivot holes in members 38 and 42 may be horizontal slots in place of circular holes, so that the movement of the rod 4'! around the fulcrum 4| as a center will not cause horizontal movement in members 38 and 42 allowing these members free, unobstructed vertical movements in normal operation. a

The clutch 3B'is shown in my apparatus for the protection of the diaphragm 43' and slide link 22. In case of prolonged periods of operation of electric motor 33, when slide link 22 reaches either end of its travel, the.clutch 36 slips thereby protecting slide link 22 and diaphragm 43 from forced movements, beyond normal limits as well as avoiding undue strain on the motor. Other means of accomplishing the same results may be used since this feature of the apparatus is not a part of my invention.

In addition, to simplify the figure, supports fo the electric motor-clutch-v'olume displacer assembly, are not shown, Supports for these and other members of my apparatus may be of conventional design and should be such that they maybe adaptable for use with any or all engines, stationary or automotive.

The liquid fuel and gaseous fuel carburetors for use with my control apparatus, 'can be of conventional design, and it is not necessary to use 7 carburetors of special or uncommon manufacture. w

While one embodiment of my control system has been described in detail, it willbe obvious to those skilled in the art that many changes and alterations of the component parts as to specific may be made and yet remain within the intended scope of my invention. ,7

I claim:

1. In a charge-forming device for vaporizing and carbureting fuels containing superatmospheric vapor pressure components including a vaporizing chamber for separating the fuel into liquid and gaseous fuels, carbureting means for the liquid fuel and carbureting means for the gaseous fuel, a fuel-air intake tube connected with the liquid carbureting means and a fuelair intake tube connected with the gaseous carbureting means, a valve in each of the intake tubes to control the air flow and thereby the fuel flow therethrough, said valves being so connected that when one valve is moved toward closed position, the other valve is moved toward open position to thus vary the relative proportion of fuel flowinduced by air flow through the respective carbureting means, the improvement comprising electrical motive power means operably consaid circuit and associated with the vaporizing chamber for controlling the energization of the electrical motive power means, said means being actuated by an ,increase'in the accumulated vol ume of liquid fuel in the vaporizing chamber to energize the electrical motive power means to move the valve controlling the induction of liquid fuel toward open position and the valve controlling the induction of gaseous fuel toward closed position and by a decrease'in the accumulated volume of liquid fuel to energize the electrical motive power means to move said valves in the reverse direction.

2. In a charge-forming devicefor vaporizing and carbureting fuels containing superatmospherlc vapor pressure components'dncluding a vaporizing chamber for separatingthe fuel into liquid and gaseous fuels, carbureting means for the liquid fuel and carbureting means for the gaseous fuel, a fuel-air intake tube connected with the liquid carbureting means and a fuelair intake tube connected with the gaseous carbureting means, a valve in-eachof the intake tubes to control the airflow and thereby the fuel flow therethrough,'saidvalves being so connected that when one valve is moved'toward closed position, the other valve is moved toward open posi-. tion to thus vary the relative proportion of fuelv flow induced by air flow through the respective carbureting means, the improvement comprising electrical motive power means operably connected 7 with said valves, said electrical motive power means being reversible to vary the relative valve position and thereby the relative proportion of liquid to gaseous fuel flowinduoedby said/car bureting means, means controlling the temperature of vaporization, an electrical circuit for said motive power means, and means connected in said circuit and associated with thevaporizing chamber for controlllng the energization. of the electrical motive power means, said means .being actuated by an increase in the accumulated volume of liquid fuel in the vaporizing chamber to energize the electrical motive power'means to move the valve controlling the induction of liquid fuel toward open position and the valve controlling the induction of gaseous fuel toward closed position and by a decrease in the accumulated volume of liquid fuel to energize the electrical motive power means to move said valves in the reverse direction.

3. In a charge-forming device for vaporizing and carbureting fuels containing superatmospheric vapor pressure components including a vaporizing chamber for separating, the fuel into liquid and gaseous fuels, carbureting means for the liquid fuel and carbureting means for the. I gaseous fuel, a fuel-air intake tube connected with the liquid carbureting means and a fuel-air intake tube connected with the gaseous carbureting means, a valve in each of the intake tubes to control the air flow and thereby the fuel flow therethrough, said valves being so connected that when one valve is moved toward closed position, the other valve is moved toward open position to thus vary the relative proportion of fuel flow induced by air flow through the respective car- Cal tion chamber having contact means thereon, an electrical switch in the vaporization chamber above the level of accumulated liquid fuel connected in the electrical circuit and actuated by said contact means on an increase in the accumulated volume of liquid fuel to energize the electrical motive power means to move the valve controlling the induction of liquid fuel toward open position and. the valve controlling the induction of gaseous fuel toward closed position, and an electrical switch in the vaporization chamber below the level of accumulated liquid fuel connected in the electricalcircuit and actuated by said contact means on a decrease in the accumulated volume of liquid fuel to energize the electrical motive power means to move said valves in the reverse direction. f

4. In a charge-forming device for vaporizing and carbureting fuels containing superatmospheric vapor pressure components including a vaporizing chamber for separating the fuel into liquid and gaseous fuels, carbureting means for theliquid fuel and carbureting means for the gaseous fuel, a fuel-air intake tub connected with the liquid carbureting means and afuel-air intake tube connected with the gaseous carbureting means, a valve in each of the intake tubes to control the air flow and thereby the fuel flow therethrough, said valves being so connected that when one valve is moved toward closed position, the other valve is moved toward open position to thus vary the relativeproportion of fuel flow induced by air flow through therespective carbureting means, the improvement comprising electrical motive power means operably connected with said valves, said electrical motive power means being reversible to vary the relative valve position and thereby the relative proportion of liquid to gaseous fuel flow induced by said carbureting means, means controlling the temperature of vaporization, an electrical circuit for said motive power means, a relay connected into the electrical circuit, means maintaining a constant pressure in the vaporization chamber, a float in said vaporization chamber having contact means thereon, an electrical switch in the vaporization chamber above the level of accumulated liquid fuel connected in the electrical circuit and actuated by said contact means on an increase in the accumulated volume of liquid fuel to energize the electrical motive power means to move the valve controlling the induction of liquid fuel toward open position and the valve controlling the induction of gaseous fuel toward closed position, and an electrical switch in the vaporization chamber below the level of accumulated liquid fuel connected in the electrical circuit and actuated vaporizing chamber for separating the fuel into liquid and gaseous fuels, carbureting means for the liquid fuel and carbureting means for the gaseous fuel, a fuel-air intake tube connected with the liquid-carbureting means and afuel-air intake tube connected with the gaseous car bureting means, a valve in each of the intake tubes to control the air flow and thereby the fuel flow therethrough, said valves being so connected that when one valve is moved toward closed position, the other valve is moved toward open position to thus vary the relative proportion of fuel flow induced by air flow through the respective carbureting means, the improvement comprising electrical motive power means operably connected withsaid jvalves, said electrical motive power means being reversible to' vary the relative valve position, and thereby .the relative proportion of liquid to gaseous fuel flow induced by said carbureting' means, means controlling the temperature of vaporization, an electrical circuit for's'aid motive power'meanaa float in saidvaporization chamber having contact-means thereon; an electrical switch in the vaporization chamber -{above* the level vof accumulated liquid fuel 'connected m" the electrical circuit and actue ated bysaid contact means onyan increasein the accumulated volume of liquijdfuel to energize the 6. A charge-forming device for vaporizing and carbureting fuels' containing superatmospheric vapor pressure components comprising a vapori'zing chamber for separating the fuel into liquid 7 and gaseous .fuels,.carbureting means for the liquid fuel and carbureting means for the gaseous fuel connected with the vaporizing chame ber, afuel-airintake tube connected with the liquid carbureting means and a fuel-air intake tube connected with the gaseous carbureting- Y electrical'motive power meansto' move'the valve controlling the induction of liquid fuel; toward means, means in said fuel-air intake tubes for proportioning the relative air-flow therethrough and hence the relative proportions of liquid and gaseous fuel flow induced to said carbureting means, electrical motive power means operably connected with the proportioning means, said electrical motive power means being reversible to vary said proportioning means and hence the relative'induction of said liquid and'gaseous fuels in accordance with the volume of liquid fuel accumulated in the vaporizing chamber.

7. A charge-forming device for vaporizing and carbureting fuels containing superatmospheric vapor pressure components comprising a vaporizing chamber for separating the fuel intoliquid and gaseous fuels, carbureting means for the liquid fuel and carbureting means for the gas- 5 eouslfuel connected with the vaporizing chamber," a fuel-air intake tube connected with the liquid carbureting means and a fuel-air intake tube connected with the gaseous carbureting means, means in said fuel-air intake tubes for proportioning therelative air-flow therethrough and hence the relative proportions of liquid and gaseous fuel flow induced to said carbureting means, electrical motive power means operably connected with the proportioning means, said electrical motive power means being reversible to vary said proportioning means and thereby the relative quantities of liquid to gaseous fuel induced in said carbureting means, an electrical circuit for said motive power means, means connected in said circuit and associated with the vaporizing chamber for controlling the energization of the electrical motive power means to vary said proportioning means and hence the relative induction of said liquid and gaseous fuels in accordance with the volume of liquid fuel accumulated in the vaporizing chamber, and a volume displacer associated with said electrical motive power means and actuated thereby to vary the volume of accumulated liquid fuel in the vaporizing chamber and tend to maintain a substantially-constant liquid level therein.

' OWEN L. GARRETSON. 

